Traditional miso contains barley, a gluten-containing grain. However, there are some companies, such as Great Eastern Sun which make miso from alternate ingredients such as soy, chickpeas, and rice (their misos are also certified organic and kosher). Additionally, as miso soup is usually made using a fish broth, using a vegetable broth in its place, makes the soup an option for vegetarian/vegan diners and those with fish allergies.